[News] Silicon Photonics Breakthrough: High-Power Frequency Comb Achieved on Chip

A research team led by Professor Michal Lipson at Columbia University has achieved a major breakthrough in silicon photonics, as reported in the latest issue of Nature Photonics. The team successfully demonstrated a high-power frequency comb light source integrated directly on a silicon photonic chip. The innovation enables the generation of dozens of wavelengths from a single laser, potentially replacing the multiple lasers traditionally required in optical transceiver modules — a significant advancement for AI and data center optical interconnects.

High-Power Laser “Purified” into Multi-Wavelength Light Source

While silicon photonic chip can already integrate key components such as waveguide, modulator, and photodetector — as seen in co-packaged optics (CPO) architectures — they still rely on external laser sources, often requiring multiple wavelengths. The Lipson group’s key innovation lies in generating a stable, multi-wavelength optical source directly on-chip.

The researchers employed a multimode laser diode as a high-power optical source. Despite high brightness, such lasers’ emission typically lacks stability. To address this, the team developed a locking mechanism that stabilizes and “purifies” the laser output, reshaping the light through silicon photonic structures to enhance both stability and coherence.

Once stabilized, nonlinear optical effects within the chip further split the single high-intensity beam into multiple evenly spaced wavelengths, forming a frequency comb. The result is a compact, high-power, and highly stable optical source capable of producing multi-channel light output from a single laser, reducing size and improving energy efficiency.

Paving the Way for AI and Data Center Optical Interconnects

As AI and high-performance computing (HPC) continue to drive surging data center power demands, optical interconnect is emerging as a key solution for lowering energy consumption and increasing bandwidth. Conventional optical modules often rely on more than a dozen lasers, increasing both cost and thermal load. The Lipson team’s innovation could enable single-chip optical modules, paving the way for miniaturized CPO package and optical transceiver in next-generation server.

Beyond data center, the researchers note that this technology also has the potential to advance spectroscopy, quantum sensing, and LiDAR applications. With silicon photonics increasingly integrating light sources, transmission, and computation on a single platform, the industry is moving toward a new era of higher efficiency and tighter system integration.

(Photo credit: FREEPIK)